How Does Pouring Polygons Over Pads Affect Solder Ability?

[RyanLott]

Hello.

First off. Thank you for this academy. I have learned so much so far. Great stuff and I appreciate your hard work.

My question is... does pouring polygons effect the solder ability of components? Or does it not matter since they are SMD? I understand that you are doing it to control the current/heat/IR-Drop, but I was just wondering if there are any "gotchas" to look out for.

Thanks, Ryan

[robertferanec]

Hello Ryan.

if you are using an assembly house to fit SMD components, using polygons or thermal relief for these connections don't have any special impact for soldering. The PCB is heated up (including the polygons), the tin is melted, SMD components are soldered and PCB is cooled down.

Hand soldering of SMD components connected to polygons is usally without problems (it may be a little bit tricky when connected to GND plane, but still ok).

However, using polygons have impact on through hole components soldered manually. For two layer PCB it is not so visible, but if you have for example four GND internal layers and you are trying to solder a through hole GND pin connected directly to this four GND planes, you may have problems (the heat from soldering iron tip is taken away and you may need to use a powerful soldering iron or thicker tip to be able to solder the pin). For multiplayer PCBs we always use thermal relief for GND pins, however, if only one polygon on one layer is connected to the pin (e.g. for power polygons), we use direct connection, no problem.